/**
 * @param {number[]} nums
 * @return {number}
 */
var singleNonDuplicate = function(nums) {
    let record = {}
    for(let i in nums){
        if(!record.hasOwnProperty(nums[i])){
            record[nums[i]] = null
        }else{
            delete record[nums[i]]
        }
    }
    return Object.keys(record)[0]
};
let t1=singleNonDuplicate([1,1,2,3,3,4,4,8,8])
let t2=singleNonDuplicate([3,3,7,7,10,11,11])
console.log("t1", t1)
console.log("t2", t2)